WO2025259474A1

WO2025259474A1 - Hybrid plasma chamber with split top electrode to reduce ion tilting and plasma non-uniformity

Info

Publication number: WO2025259474A1
Application number: PCT/US2025/032096
Authority: WO
Inventors: Juline Shoeb; Alexander Miller PATERSON
Original assignee: Lam Research Corp
Current assignee: Lam Research Corp
Priority date: 2024-06-12
Filing date: 2025-06-03
Publication date: 2025-12-18
Anticipated expiration: 2026-12-12

Abstract

A system for generating plasma. The system including a plasma chamber configured for generating plasma, wherein the plasma chamber includes a lower electrode located within an electrostatic chuck (ESC) having a central axis in a vertical direction. The system including a split top electrode disposed above the lower electrode, wherein the split top electrode includes a main electrode and an outer electrode surrounding the main electrode in a horizontal direction referenced to the central axis. The system including a dielectric separating the main electrode and the outer electrode. The system including at least one transformer coupled plasma (TCP) coil vertically disposed over the split top electrode. The system including an edge ring surrounding the lower electrode and ESC in the horizontal direction.

Description

HYBRID PLASMA CHAMBER WITH SPLIT TOP ELECTRODE TO REDUCE ION TILTING AND PLASMA NON-UNIFORMITY

TECHNICAL FIELD

[0001] The present embodiments relate to semiconductor fabrication, and more specifically to systems and methods for reducing tilting of ions with improved plasma uniformity using a capacitively coupled plasma chamber with a split top electrode, and a hybrid capacitively coupled and transformer coupled plasma chamber with a split top electrode.

BACKGROUND OF THE DISCLOSURE

[0002] Many modern semiconductor chip fabrication processes such as plasma etching processes are performed within a plasma processing chamber in which a substrate, e.g., wafer, is supported on an electrostatic chuck (ESC). In plasma etching processes, the wafer is exposed to a plasma generated within a plasma processing volume. Plasma contains various types of radicals, electrons, as well as positive and negative ions. The chemical reactions of the various radicals, electrons, positive ions, and negative ions are used to etch features, surfaces and materials of a wafer.

[0003] For example, when a process gas is supplied into the plasma processing chamber, one or more radio frequency (RF) signals provide power that are applied to one or more coils and/or electrodes of the plasma processing chamber to form an electric field. The process gas is turned into plasma by the RF signals, thereby performing plasma etching on a predetermined layer disposed on the wafer. Unfortunately, during wafer processing, the plasma non-uniformity arising from plasma generation zones may result in ions striking the wafer with a non-vertical direction (e.g., ion tilt angles) occurring all across the wafer and along the extreme edge of the wafer which may cause tilted etch features in the wafer.

[0004] For illustration, current technology may use one top electrode that applies high frequency to produce plasma density, and a lower electrode beneath the plasma that applies a low frequency or a mixture of high and low frequency in order to produce high density plasma with increased ion energy for faster etching with narrow critical dimensions. However, because of plasma generation and loss in the camber wall, there may be a center heavy ion density or ion flux profile (i.e., increase towards a center of a substrate), leading to plasma nonuniformity across a surface of the substrate. In particular, the high frequency may be responsible for slowing down electromatic waves producing a center heavy, non-uniform plasma profile. More specifically, such plasma nonuniformity in turn produces a variation in sheath thickness on the substrate that can provide a titled edge feature.

[0005] It is in this context that embodiments of the disclosure arise. SUMMARY

[0006] The present embodiments relate to plasma processing systems for improving plasma uniformity to achieve minimal ion tilt across the wafer using a capacitively coupled plasma chamber with a split top electrode, and a hybrid capacitively coupled and transformer coupled plasma chamber with a split top electrode. Several inventive embodiments of the present disclosure are described below.

[0007] Embodiments of the present disclosure provide for a system for generating plasma. The system includes a plasma chamber configured for generating plasma, wherein the plasma chamber includes a lower electrode located within an electrostatic chuck (ESC) having a central axis in a vertical direction. The system includes a split top electrode disposed above the lower electrode, wherein the split top electrode includes a main electrode and an outer electrode surrounding the main electrode in a horizontal direction referenced to the central axis. The system includes a dielectric separating the main electrode and the outer electrode. The system includes at least one transformer coupled plasma (TCP) coil vertically disposed over the split top electrode. The system includes an edge ring surrounding the ESC, substrate, and/or lower electrode in the horizontal direction. The vertical position of the lower electrode within the ESC with respect to the edge ring may change in different configurations, such that the lower electrode may be at a level horizontally with at least a portion of the edge ring, or may be below the edge ring.

[0008] Other embodiments of the present disclosure provide for another system for generating plasma. The system includes a plasma chamber configured for generating plasma, wherein the plasma chamber includes a lower electrode located within an ESC having a central axis in a vertical direction. The system includes an edge ring surrounding the lower electrode and ESC in a horizontal direction referenced to the central axis. The system includes a top electrode disposed above the lower electrode, wherein the top electrode extends radially beyond the edge ring in the horizontal direction, such that the outer diameter of the top electrode is larger than the outer diameter of the edge ring. The system includes at least one TCP coil vertically disposed over the long electrode.

[0009] Still other embodiments of the present disclosure provide for another system for generating plasma. The system includes a plasma chamber configured for generating plasma, wherein the plasma chamber includes a lower electrode located within an ESC having a central axis in a vertical direction. The system includes a split top electrode disposed above the lower electrode, wherein the split top electrode includes a main electrode and an outer electrode surrounding the main electrode in a horizontal direction referenced to the central axis. The system includes a dielectric separating the main electrode and the outer electrode. The system includes an edge ring surrounding the lower electrode and ESC in the horizontal direction. In the system, the main electrode and the outer electrode have a vertical height difference between a bottom surface of the main electrode and a bottom surface of the outer electrode. In one embodiment, the vertical height difference is related to a thickness of the main electrode compared to a thickness of the outer electrode. In another embodiment, the vertical height difference is calculated as the difference between a distance between the bottom surface of the main electrode above a top surface of the ESC and a distance between the bottom surface of the outer electrode above the top surface o of the ESC.

[0010] These and other advantages will be appreciated by those skilled in the art upon reading the entire specification and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The embodiments may best be understood by reference to the following description taken in conjunction with the accompanying drawings.

[0012] FIG. 1 A illustrates an embodiment of a capacitively coupled plasma processing system utilized for etching operations including a split top electrode, in accordance with one embodiment of the present disclosure.

[0013] FIGS. 1B-1C illustrate embodiments of plasma processing systems including a split top electrode, wherein one of the split sections of the top electrode is thicker, in accordance with one embodiment of the present disclosure.

[0014] FIG. 2 illustrates an embodiment of a hybrid plasma processing system utilized for etching operations including a split top electrode used for capacitive coupling and at least one coil used for inductive coupling, in accordance with one embodiment of the present disclosure. [0015] FIG. 3 illustrates an embodiment of a hybrid plasma processing system utilized for etching operations including a long top electrode used for capacitive coupling and at least one coil used for inductive coupling, in accordance with one embodiment of the present disclosure. [0016] FIG. 4A illustrates non-uniform plasma density and an edge sheath contributing to tilting of ions at an edge of a substrate.

[0017] FIG. 4B illustrates a uniform plasma density and an edge sheath that is generated by a capacitively coupled plasma chamber with a split top electrode, and a hybrid capacitively coupled and transformer coupled plasma chamber, in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION

[0018] Although the following detailed description contains many specific details for the purposes of illustration, anyone of ordinary skill in the art will appreciate that many variations and alterations to the following details are within the scope of the present disclosure. Accordingly, the aspects of the present disclosure described below are set forth without any loss of generality to, and without imposing limitations upon, the claims that follow this description. [0019] Generally speaking, the various embodiments of the present disclosure describe plasma processing systems for reducing ion tilt in the entirety of the wafer. In particular, in one embodiment, a capacitively coupled plasma processing system includes a top electrode that is split into two sections, wherein each section is independently controllable to deliver similar or different plasma power. In other embodiments, the top electrode is split into more than two sections, wherein each section is independently controllable to deliver similar or different plasma power. In another embodiment, a hybrid processing system includes a top electrode for providing capacitively coupled power, wherein the top electrode is split into two or more sections that are each independently controllable to deliver similar or different plasma power, and a transformer coupled plasma (TCP) coil placed on top of a dielectric gap between sections of the split top electrode. In still another embodiment, a hybrid processing system includes a top electrode for providing capacitively coupled power, wherein the top electrode remains unsplit, and a TCP coil placed at an edge of the top electrode above a dielectric located beyond the outer diameter of the top electrode. Each of these plasma processing systems of the various embodiments optimally controls plasma density/flux on the wafer in order to minimize plasma non-uniformity.

[0020] In particular, current technology may use one top electrode that applies high frequency to produce plasma density, and a lower electrode beneath the plasma that applies a low frequency or a mixture of high and low frequency in order to produce high density plasma with increased ion energy for faster etching with narrow critical dimensions. However, because of plasma generation and loss in the camber wall, there may be a center heavy ion density or ion flux profile (i.e., increase towards a center of a substrate), leading to plasma nonuniformity across a surface of the substrate. For instance, the high frequency may be responsible for slowing down electromatic waves producing a center heavy, non-uniform plasma profile. More specifically, such plasma nonuniformity in turn produces a variation in sheath thickness on the substrate that can provide a titled edge feature. On the other hand, with the use of a split top electrode including two or more sections, each section can deliver its own high frequency power for plasma generation. These individually controlled power signals can be adjusted to produce very uniform plasma across a surface of a substrate, which leads to more uniform ion tilt across the substrate. Advantages of the various embodiments, disclosing plasma processing systems including a capacitively coupled plasma chamber with a split top electrode, and a hybrid capacitively coupled and transformer coupled plasma chamber with a split top electrode, include controlling ion tilt (i.e., minimize ion tilt) globally across a wafer resulting from improved plasma uniformity. Other advantages of present embodiments include the ability to mitigate plasma non-uniformity by optimizing power delivered to sections of a split top electrode, and/or varying depths of the sections of the split top electrode, and/or placing a TCP coil over a top electrode (i.e., split or unsplit). These mitigation techniques provide for better uniformity of plasma spread across a surface of the wafer and especially at the edge and/or better uniformity of features across the surface of the wafer. Advantages of present embodiments of plasma processing systems used for etching substrates provide operational improvements over existing CCP plasma chambers often produce edge or center heavy plasma because of the inability to perform mitigation of ion tilt.

[0021] With the above general understanding of the various embodiments, example details of the embodiments will now be described with reference to the various drawings. Similarly numbered elements and/or components in one or more figures are intended to generally have the same configuration and/or functionality. Further, figures may not be drawn to scale but are intended to illustrate and emphasize novel concepts. It will be apparent, that the present embodiments may be practiced without some or all of these specific details. In other instances, well-known process operations have not been described in detail in order not to unnecessarily obscure the present embodiments.

[0022] Throughout the specification the terms substrate and wafer may be used interchangeably. Generally, plasma processing may be performed on a substrate and/or wafer to etch features on a plasma-facing surface, or to deposit layers on the plasma-facing surface of the substrate and/or wafer.

[0023] FIG. 1 A illustrates an embodiment of a capacitively coupled plasma (CCP) processing system 100 utilized for etching operations including a split top electrode, in accordance with one embodiment of the present disclosure. Generally, exemplary CCP processing system 100 can be utilized for operations including etching and/or depositing films, such as for operations used to perform plasma processing of a substrate 120.

[0024] In particular, FIG. 1 A illustrates an exemplary embodiment of the plasma processing system 100 utilized for etching operations that is configured as a CCP processing system, and includes a CCP plasma process chamber 102 that is configured for generating plasma. The plasma process chamber 102 includes a substrate support or pedestal, such as an electrostatic chuck (ESC) 118. The ESC 118 is centered about a central axis 175. In embodiments, the ESC may have several circular rings with different material types to achieve a certain capacitive coupling between the ESC and an edge ring 126, which may be separately powered by a power source 151 through coupling ring 127 (e.g., a tunable edge sheath or TES ring). A lower electrode 122 may be embedded within the ESC 118. The vertical position of the lower electrode within the ESC with respect to the edge ring may change in different configurations, such that the lower electrode may be at a level horizontally with at least a portion of the edge ring, or may be below the edge ring. One or more power sources may be coupled to components of the plasma processing system 100. A substrate 120 may be placed on the pedestal for processing, wherein the substrate or wafer 120 is processed to make one or more semiconductor chips.

[0025] Facing the pedestal is a top electrode 101 A that is disposed over the lower electrode 122. Between the top electrode 101A and the lower electrode 122 is a gap forming a processing volume within which a plasma 130 may be formed. As shown, the top electrode 101 A may be configured as a split top electrode that is split into two sections, in one embodiment. For example, the split top electrode includes a main electrode 124 and an outer electrode 123, that may be shaped as a ring. The outer electrode surrounds the main electrode in a horizontal direction referenced to the central axis 175. In other embodiments, the top electrode 101 A is split into more than two sections, wherein each section is independently controllable to deliver similar or different plasma power. Further, the top electrode 101 A may include an extension (not shown) that surrounds the outer electrode, and may consist of a dielectric material, wherein the extension may be configured as a ring.

[0026] In addition, a dielectric 125 may be disposed between and separate the main electrode 124 and the outer electrode 123, wherein the dielectric may be shaped as a ring. In one implementation, the dielectric is disposed over the interface between the ESC 118 and the edge ring 126. For example, the a portion of the dielectric 125 overlaps at least a portion of the edge ring 126 in a vertical direction parallel to the central axis 175.

[0027] In one implementation, the dielectric 125 is of a sufficient width to separate plasma being generated (e.g., in plasma generation zones) by each of the main electrode and the outer electrode 123. For example, the dielectric may have a width between the main electrode 124 and the outer electrode 123 between 2 to 55 millimeters (mm) in a horizontal direction that is perpendicular to the central axis 175. In one implementation, the width of the dielectric 125 is approximately 3 centimeters (cm).

[0028] The radio frequency (RF) power may be supplied independently and separately to each of the main electrode 124 and the outer electrode 123 to generate plasma. As shown, an RF power source 160, tuned by match network 165, supplies RF power to the main electrode 124. In addition, an RF power source 161, tuned by match network 166, supplies RF power to the outer electrode 123.

[0029] In particular, different RF power can be delivered for generating plasma. The characteristics of the RF power signals delivered to the main electrode and the outer electrode can be adjusted to generate a uniform plasma globally across the substrate 120. For example, the power signals are adjusted to control the ion density and/or flux on the substrate, such as to achieve uniform ion density and/or flux globally across the substrate resulting in minimizing plasma non-uniformity globally across the substrate. In particular, one or more parameters for the RF power signals to the main electrode and outer electrode are tunable to selectively affect plasma generation across the substrate, wherein the parameters include, in part, frequencies of the RF power signals and/or power levels of the RF power signals. In one exemplary embodiment, a high frequency RF power signal may be supplied to the main electrode and a low frequency RF power signal may be supplied to the outer electrode, wherein a dielectric separates the main electrode and the outer electrode in order to prevent cross-over of the RF power signals between the two electrodes. In another exemplary embodiment, the powers of the RF power signals delivered to the main electrode and the outer are selectable to selectively affect plasma generation across the substrate. As such, by adjusting the RF power signals delivered to the main electrode and the outer electrode, selective control of angular ion tilt is achieved globally across the substrate, such as during etching processes. In that manner, by selectively tuning one or more parameters for the RF power signals to the main electrode and outer electrode, plasma is generated more uniformly across the substrate, especially at the edge of the substrate, which in turn provides for uniform ion density and/or flux globally across the substrate. That is, instead of a plasma density that is center dependent over the substrate, by tuning one or more parameters (e.g., power) of the RF power signals to the main electrode and/or outer electrode, the plasma density and/or plasma uniformity is controllable over the substrate, and especially at the outer edge of the substrate, thereby providing selective control of angular ion tilt globally across the substrate.

[0030] In general, the RF power being supplied to either the main electrode 124 or the outer electrode 123 may be of sufficient frequency to generate plasma. For example, the RF frequency may range between 5 megahertz (MHz) to over 100 MHz, or higher (e.g., to over 200 MHz). In some implementations the RF frequency may range as low as 400 kilohertz (kHz), or lower.

[0031] In embodiments, the frequencies of the RF power signals to the main electrode 124 and the outer electrode 123 are selectable, and may be similar or different. In one embodiment, the frequency of the RF power signal supplied to the main electrode 124 is higher than the frequency of the RF power signal supplied to the outer electrode. In embodiments, the power of the RF power signals to the main electrode 124 and the outer electrode 123 are selectable, and may be similar or different. Also, the power of the RF power signal supplied to the main electrode may be higher than the power of the RF power signal supplied to the outer electrode. For purposes of illustration, the RF power signal supplied to the main electrode may have a frequency of 60 MHz that is delivered at 6 kilowatts (6 kW), whereas the RF power signal supplied on the outer electrode may have a frequency of 10 MHz that is delivered at 3 kilowatts (3 kW). In another illustration, the RF power signal supplied to the main electrode may have a frequency of 60 MHz that is delivered at 6 kilowatts (6 kW), whereas the RF power signal supplied to the outer electrode may have a frequency of 30 MHz that is delivered at 3 kilowatts (3 kW). In still another illustration the RF power signals supplied to the main electrode and the outer electrode each may have a frequency of 60 MHz, wherein the power delivered to the main electrode is at 6 kilowatts (6 kW), and the power delivered to the outer electrode is at 3 kilowatts (3 kW).

[0032] Further, a bias signal generated by a bias power source 150 provides a bias voltage to the lower electrode 122 embedded within the ESC 118, wherein the bias signal may be RF, mixed RF (e.g., high and low frequency RF), or DC. For example, the bias signal may be an RF power signal that is tuned via an optional match circuit (not shown), wherein the match circuit is electrically coupled to the lower electrode 122 located within the ESC 118. In one implementation, the bias signal may be a mixed RF power signal, including a higher frequency RF power signal, and a lower frequency RF power signal.

[0033] The plasma process chamber 102 also includes the edge ring 126 which surrounds the ESC 118 and/or the lower electrode 122. As an example, the edge ring 126 is fabricated from a conductive material, such as silicon, boron doped single crystalline silicon, silicon carbide, an alloy of silicon, or a combination thereof. In embodiments, the edge ring 126 has an annular body, such as a circular body, or ring-shaped body, or dish-shaped body. The edge ring 126 has an inner radius and an outer radius. The edge ring 126 performs many functions including positioning the substrate 120 on the ESC 118, confining plasma to an area above the substrate 120, protecting the ESC 118 from erosion by ions of the plasma, and shielding underlying components of the plasma chamber 102 from being damaged by ions of the plasma. Further, the edge ring is configured to improve performance at the edge of the substrate. For example, by varying an amount of the power coupled to the edge ring, plasma density of the plasma at the edge region, sheath uniformity of the plasma at the edge region, etch rate uniformity of the plasma at the edge region, and ion tilt at which the substrate is etched in the edge region may be controlled. The power supplied to the edge ring 126 may be generated by TES power source 181 that is configured for generating RF power, wherein the TES power source 181 is electrically coupled to the edge ring 126 through a coupling ring 127, and optionally via a match circuit (not shown). [0034] In addition, plasma processing chamber 102 of FIG. 1 may optionally include a C- shroud 150 that extends from the top electrode 101A, and/or from an extension (not shown) to the top electrode 101 A, towards the ESC 118 to provide additional plasma containment. The C- shroud may have a plurality of apertures or slots to allow gas and byproducts to flow out of the C-shroud. The C-shroud may be grounded.

[0035] In another embodiment, gas source(s) 114 are connected to the plasma process chamber 102 and are configured to inject the desired process gas(es) into the plasma process chamber 102. As an example of plasma formation, after providing one or more bias signals (e.g., RF and/or DC) to the ESC 118 and injecting process gas(es) into the plasma process chamber 102, plasma 130 is then formed between the top electrode 101 A and the ESC 118. The plasma 130 can be used to etch the surface of the substrate 120. Although not shown, pumps are connected to the plasma chamber 102 to enable vacuum control and removal of gaseous byproducts from the plasma chamber during operational plasma processing.

[0036] In some embodiments, the system may include a controller 116 that is used for controlling various components of the plasma processing system 100. In one example, the controller 116 can be connected to the plasma generators (e.g., RF power source 160, RF power source 161, TES power source 181, bias power source 180), to the gas source(s) 114 that are coupled to the plasma process chamber 102, and to other components. The controller 116 includes a processor, memory, software logic, hardware logic and input and output subsystems from communicating with, monitoring and controlling the plasma processing system 100. In some embodiments, the controller 116 includes one or more recipes including multiple set points and various operating parameters (e.g., voltage, current, frequency, pressure, flow rate, power levels, temperature, timing parameters, process gases, mechanical movement of the substrate 120, etc.) for operating the plasma processing system 100. For example, depending on the processing being performed, the controller 116 manages the delivery of process gases delivered from the gas source(s) 114 to achieve a designed processing condition, such as to etch features and/or deposit or form films over the substrate 120. The chosen gases are then distributed in a space volume defined between the top electrode 101 A and the substrate 120 resting over the ESC 118.

[0037] FIGS. 1B-1C illustrate embodiments of plasma processing systems including a split top electrode including two sections, wherein one of the sections of the top electrode is stepped and/or thicker, in accordance with one embodiment of the present disclosure. The benefits provided by the split top electrodes as illustrated in FIGS. 1B-1C include improved performance, such as improved plasma uniformity globally across the wafer. In particular, the thickness of the outer electrode (i.e., one of the sections) provides an additional tuning parameter to affect plasma generation across the substrate. The thickness of the outer electrode is selectable to help achieve uniform plasma generation globally across the substrate, especially at the edge of the substrate, providing for uniform ion density and/or flux globally across the substrate, which in turn provides for selective control of angular ion tilt globally across the substrate. The split top electrode including a stepped section may be utilized in any plasma processing system described herein. For example, either of the split top electrode 10 IB shown in FIG. IB or split top electrode 101C shown in FIG. 1C may be incorporated into the plasma processing system 100 of FIG. 1 A and/or plasma processing system 200 of FIG. 2.

[0038] Generally, and as previously described in relation to FIG. 1 A, each of the split top electrodes shown in FIGS. IB and 1C includes a main electrode and an outer electrode, powered by different RF power signals. In particular, one or more parameters for the RF power signals to the main electrode and outer electrode are tunable to selectively affect plasma generation across the substrate, wherein the parameters include, in part, frequencies of the RF power signals and/or power levels of the RF power signals. In one exemplary embodiment, a high frequency RF power signal may be supplied to the main electrode and a low frequency RF power signal may be supplied to the outer electrode, wherein a dielectric electrically separates the main electrode and the outer electrode. In another exemplary embodiment, the powers of the RF power signals delivered to the main electrode and the outer electrode are selectable to selectively affect plasma generation across the substrate. In that manner, by selectively tuning one or more parameters for the RF power signals to the main electrode and the outer electrode, plasma density and/or plasma uniformity is controllable across the substrate, such that plasma is generated more uniformly globally across the substrate, especially at the edge of the substrate, which also provides for uniform ion density and/or flux globally across the substrate, which also provides for selective control of angular ion tilt globally across the substrate.

[0039] For purposes of illustration only, each of FIG. IB and FIG. 1C may provide an expanded view of the highlighted portion 170 of the plasma processing system 100 of FIG. 1 A, showing the split top electrode in relation to an ESC 118 (including a lower electrode) and/or an edge ring 126, wherein like components are represented by like reference numerals. For example, the plasma processing system may include a plasma chamber configured for generating plasma, wherein the plasma chamber includes a lower electrode (not shown) located within an ESC 118 that is configured to support a substrate 120. An edge ring 126 surrounds the ESC 118. Further, a split top electrode is disposed above the ESC, wherein the split top electrode includes a main electrode and an outer electrode that surrounds the main electrode. A dielectric separates the main electrode and the outer electrode. In addition, another dielectric optionally may surround the outer electrode, wherein the dielectric may be shaped in the form of a ring. [0040] In particular, the split top electrode includes a vertical height difference between a bottom surface of the main electrode that is above a top surface of the ESC, and a bottom surface of the outer electrode that is above the top surface of the ESC. In one embodiment, the vertical height difference is related to a thickness of the main electrode compared to a thickness of the outer electrode. In another embodiment, the vertical height difference is calculated as the difference between a distance between the bottom surface of the main electrode above a top surface of the ESC and a distance between the bottom surface of the outer electrode above the top surface of the ESC. That is, the split top electrode may include a section that is stepped or its thickness can be increased or decreased in the vertical direction (e.g., Z-direction) that is parallel to the central axis (e.g., axis 175 of FIG. 1 A) of the ESC 118. In various embodiments, a thickness of the outer electrode may be increased or decreased in the Z-direction and/or a thickness of the main electrode may be increased or decreased in the Z-direction.

[0041] For illustration, FIG. IB includes a highlighted portion 170B that corresponds with highlighted portion 170 of FIG. 1A. A split top electrode 101B includes a main electrode 124A, and an outer electrode 123A that is separated by a dielectric 125A from the main electrode 124A. In addition, another dielectric 190A optionally may surround the outer electrode 123 A, wherein the dielectric may be shaped in the form of a ring. As shown, the outer electrode 123A is thicker than the main electrode 124A, and the bottom surface 182A of the outer electrode is closer to the top surface 119 of the ESC 118 than the bottom surface 181 A of the main electrode is to the top surface 119 of the ESC 118. In other words, distance 195A between the bottom surface 182A of the outer electrode 123A and the top surface 119 of the ESC 118 is less than the distance 196A between the bottom surface 181A of the main electrode 124A and the top surface 119 of the ESC 118. In addition, a vertical height difference 197A, that is the difference between the distance 195A and distance 196A, indicates that the outer electrode 123A is stepped closer to the ESC 118 in the Z-direction than the main electrode 124A.

[0042] In one embodiment, the dielectric 125A is stepped, such that the dielectric includes an interlocking step 197 that is configured to interface with the main electrode 124A. Also, the main electrode 124 A includes an opposing interlocking step configured to mate with the interlocking step of the dielectric 125A. The (optional) interlocking step 197 is configured to provide support for the main electrode 124 A, in one embodiment. The stepped dielectric separating the main electrode and the outer electrode may be included within any of the plasma processing systems described herein. In addition, the dielectric separating the main electrode and the outer electrode may include another step to provide support for one or more of the dielectric and/or the outer electrode. Further, the dielectric 190A may be configured (e.g., stepped) to provide support to the outer electrode 123 A, and may be included within any of the plasma processing systems described herein.

[0043] In another illustration, FIG. 1C includes a highlighted portion 170C that corresponds with highlighted portion 170 of FIG. 1 A. A split top electrode 101C includes a main electrode 124B, and an outer electrode 123B that is separated by a dielectric 125B from the main electrode 123B. In addition, another dielectric 190C optionally may surround the outer electrode 123B, wherein the dielectric may be shaped in the form of a ring. As shown, the main electrode 124B is thicker than the outer electrode 123B, and the bottom surface 18 IB of the main electrode is closer to the top surface 119 of the ESC 118 than the bottom surface 182B of the outer electrode. In other words, distance 181B between the bottom surface 181B of the main electrode 124B and the top surface 119 of the ESC 118 is less than the distance 195B between the bottom surface 182B of the outer electrode 123B and the top surface 119 of the ESC 118. In addition, a vertical height difference 197B, that is the difference between the distance 196B and distance 195B, indicates that the main electrode 124B is stepped closer to the ESC 118 in the Z-direction than the outer electrode 123B.

[0044] FIG. 2 illustrates an embodiment of a hybrid plasma processing system 200 utilized for etching operations including a split top electrode 201 used for capacitive coupling and at least one coil 210 used for inductive coupling, in accordance with one embodiment of the present disclosure. The hybrid plasma processing system 200 is similar in configuration to the plasma processing system 100 of FIG. 1A, wherein like components are represented by like reference numerals, except for additional components used for generating plasma via transformer coupling.

[0045] For example, the hybrid plasma processing system 200 may include a plasma chamber 102 configured for generating plasma, wherein the plasma chamber includes a lower electrode 122 located within an ESC 118 that is configured to support a substrate 120. The ESC 118 may include a central axis 275. An edge ring 126 surrounds the ESC 118 in a horizontal direction referenced to the central axis (i.e., perpendicular to the central axis). The vertical position of the lower electrode within the ESC with respect to the edge ring may change in different configurations, such that the lower electrode may be at a level horizontally with at least a portion of the edge ring, or may be below the edge ring. Further, a split top electrode 201 is disposed above the lower electrode and/or the ESC, wherein the split top electrode includes a main electrode 124 and an outer electrode 123 that surrounds the main electrode in the horizontal direction, in one embodiment. In other embodiments, the split top electrode is split into more than two sections, wherein each section is independently controllable to deliver similar or different plasma power. A dielectric 125 separates the main electrode 124 and the outer electrode 123. In addition, another dielectric (not shown) optionally may surround the outer electrode, wherein the dielectric may be shaped in the form of a ring. A C-shroud 150 may be configured to surround the top electrode 201 and the ESC 118.

[0046] As described previously, power sources (e.g., RF power sources) are used to drive one or more of the main electrode 124, outer electrode 123, and the lower electrode 122 of the ESC 118, for purposes of generating plasma through capacitive coupling. In particular, an RF power generator 160 is electrically coupled to the main electrode 124 via a match circuit 165, and is configured to supply a high frequency RF power signal, for example. Also, an RF power generator 161 is electrically coupled to the outer electrode 123 via match circuit 166, and is configured to supply another high frequency RF power signal that may be of a lower frequency than that of the RF power signal delivered to the main electrode 124. In addition, a bias power generator 150 is electrically coupled to the lower electrode 122 and is configured to supply a bias voltage via a bias signal to the lower electrode, wherein the bias signal may be a DC signal, RF signal, mixed RF and DC signal, or a mixed RF signal (e.g., low and high frequencies). RF power may also be supplied to the edge ring 126 via the TES power source 181. The hybrid plasma processing system 200 is also configured for generating plasma through inductive coupling, as described below.

[0047] As shown, the split top electrode 201 includes a main electrode 124 and an outer electrode 123, powered by different RF power signals. In particular, one or more parameters for the RF power signals to the main electrode and outer electrode are tunable to selectively affect plasma generation across the substrate, wherein the parameters include, in part, frequencies of the RF power signals and/or power levels of the RF power signals. In one exemplary embodiment, a high frequency RF power signal may be supplied to the main electrode and a low frequency RF power signal may be supplied to the outer electrode, wherein a dielectric electrically separates the main electrode and the outer electrode. In another exemplary embodiment, the powers of the RF power signals delivered to the main electrode and the outer electrode are selectable to selectively affect plasma generation across the substrate. In that manner, by selectively tuning one or more parameters for the RF power signals to the main electrode and the outer electrode, plasma density and/or plasma uniformity is controllable across the substrate, such that plasma is generated more uniformly globally across the substrate, especially at the edge of the substrate, which also provides for uniform ion density and/or flux globally across the substrate, which also provides for selective control of angular ion tilt globally across the substrate.

[0048] The hybrid plasma processing system 200 is configured for generating plasma 130 through inductive coupling in addition to capacitive coupling. In particular, at least one transformer coupled plasma (TCP) coil 210 is disposed vertically over the split top electrode 201. For example, the coil may wind around or may be centered about the central axis 275, wherein a cross section of the coil is shown in FIG. 2. An RF power source 195, tuned by a match network 197, supplies RF power to the at least one TCP coil 210, and managed by controller 116. For example, the RF power source 195 supplies a high or higher frequency RF power signal. That is, the RF power generator 195 is electrically coupled to the at least one TCP coil 210, and is configured to supply an RF power signal to the at least one TCP coil operating at an RF frequency. For example, the RF frequency may range between 5 megahertz (MHz) to 100 MHz, or higher. Further, the first frequency may be a baseline frequency of 10 MHz or 13.56 MHz or 27 MHz or 40MHz or 60 MHz or 100 MHz. In one implementation, the frequency of operation of the RF power source 195 is 13.56 MHz.

[0049] In one embodiment, the at least one TCP coil 210 is placed on top of or over the gap between the sections of the top split electrode 201. In particular, i.e., the at least one TCP coil 210 is located near (e.g., disposed over) the dielectric 125 that separates the main electrode 124 from the outer electrode 123. The dielectric may be configured as a ceramic type material, or any other material that is capable of allowing energy (e.g., toroidal power) to pass from the at least one TCP coil 210 to the plasma processing chamber 102. In one embodiment, the at least one TCP coil 210 and/or the dielectric overlaps at least a portion of the edge ring 126 in a vertical direction. More specifically, RF power that is applied to the at least one TCP coil 210 is configured to provide inductively coupled power into the plasma processing chamber 102 for the formation of plasma, which can further enhance etching of the surface of the substrate. For example, the RF power provided by the at least one TCP coil 210 is used to mitigate edge heavy non-uniformity in the plasma (e.g., plasma generated through capacitive coupling). In particular, the TCP coil provides an additional tuning parameter to affect plasma generation across the substrate, and more particularly at the edge of the substrate. That is, one or more characteristics of the RF power signal to the TCP coil may be selectable to help achieve uniform plasma generation globally across the substrate, and especially at the edge of the substrate, by providing for uniform ion density and/or flux globally across the substrate, which in turn provides for selective control of angular ion tilt globally across the substrate. In that manner, at least one TCP coil 210 beneficially influences the uniformity of plasma, such that ion tilt may be more vertical (i.e., perpendicular to the surface of the substrate) when striking the substrate, especially at the edge of the substrate.

[0050] In one implementation, the at least one TCP coil 210 includes a plurality of TCP coils that is oriented vertically over the split top electrode, as is shown in FIG. 2. For example, the plurality may include two or three coils, each of which winds around or may be centered about the central axis 275. In another implementation, the at least one TCP coil 210 includes a plurality of TCP coils that is oriented horizontally over the split top electrode, such that a plane including the plurality of TCP coils is approximately parallel to a top surface of the dielectric 125, which is also coplanar with top surfaces of the main electrode 124 and/or the outer electrode 123. Each of the plurality of TCP coils, that is oriented horizontally, may wind around or may be centered about the central axis 275.

[0051] FIG. 3 illustrates an embodiment of a hybrid plasma processing system utilized for etching operations including a long top electrode 324 used for capacitive coupling and at least one coil 310 used for inductive coupling, in accordance with one embodiment of the present disclosure. The hybrid plasma processing system 200 is similar in configuration to the plasma processing system 100 of FIG. 1 A, wherein like components are represented by like reference numerals, except for the use of a single top electrode, including one section instead of a split top electrode including multiple sections, and additional components used for generating plasma via transformer coupling.

[0052] For example, the hybrid plasma processing system 300 may include a plasma chamber 102 configured for generating plasma, wherein the plasma chamber includes a lower electrode 122 located within an ESC 118 that is configured to support a substrate 120. The ESC 118 may include a central axis 375. An edge ring 126 surrounds the ESC 118 in a horizontal direction referenced to the central axis (i.e., perpendicular to the central axis). The vertical position of the lower electrode within the ESC with respect to the edge ring may change in different configurations, such that the lower electrode may be at a level horizontally with at least a portion of the edge ring, or may be below the edge ring. Further, a top electrode 324 is disposed above the lower electrode and/or the ESC, wherein the top electrode is configured as an unsplit electrode (e.g., single electrode) configured to supply capacitively coupled power. In one embodiment, an outer edge of the top electrode is disposed beyond an outer edge of the edge ring 126, such as in the vertical direction, as shown. In another embodiment, the outer edge of the top electrode overlaps at least a portion of the edge ring 126, such as in a vertical direction. A dielectric 125 extends from the main electrode 324 in a radial direction (i.e., with reference to the central axis), and may be configured as a ring. In one embodiment, the dielectric is disposed beyond an outer edge of the edge ring 126, such as in the vertical direction, as shown. In another embodiment, the dielectric overlaps at least a portion of the edge ring 126, such as in a vertical direction. A C-shroud 150 may be configured to surround the top electrode 324 and the ESC 118.

[0053] As previously described, power sources (e.g., RF power sources) are used to drive one or more of the top electrode 324 and the lower electrode 122 of the ESC 118, for purposes of generating plasma through capacitive coupling. In particular, an RF power generator 160 is electrically coupled to the top electrode 324 via a match circuit 165, and is configured to supply a high frequency RF power signal, for example. Also, a bias power generator 150 is electrically coupled to the lower electrode 122 and is configured to supply a bias voltage via a bias signal to the lower electrode, wherein the bias signal may be a DC signal, RF signal, mixed RF and DC signal, or a mixed RF signal (e.g., low and high frequencies). RF power may also be supplied to the edge ring 126 through capacitive coupling via the TES power source 181 and coupling ring 127. Because the top electrode 324 overlaps and/or extends beyond the edge ring 126, plasma is generated more uniformly across the substrate 120, especially at the edge of the substrate. This extension of the top electrode also provides for uniform ion density and/or flux, as well as ion tilt, globally across the substrate, and more particularly at the edge of the substrate. The hybrid plasma processing system 300 is also configured for generating plasma through inductive coupling, as described below.

[0054] The hybrid plasma processing system 300 is configured for generating plasma 130 also through inductive coupling. In particular, at least one transformer coupled plasma (TCP) coil 310 is vertically disposed over the top electrode 324. In one implementation, the at least one TCP coil 310 includes a plurality of TCP coils that is oriented vertically over the split top electrode 324, as is shown in FIG. 3. For example, the coil may wind around or may be centered about the central axis 375. In another implementation, the at least one TCP coil 310 includes a plurality of TCP coils that is oriented horizontally over the top electrode 324. For example, each of the coils may lie within a plane that is approximately parallel to a top surface of the top electrode, wherein each of the coils may wind around or may be centered about the central axis 375.

[0055] An RF power source 195, tuned by a match network 197, supplies RF power to the at least one TCP coil 310, and as managed by controller 116. For example, the RF power source 195 supplies a high or higher frequency RF power signal. That is, the RF power generator 195 is electrically coupled to the at least one TCP coil 310, and is configured to supply an RF power signal to the at least one TCP coil operating at an RF frequency. As previously described, the RF frequency may range between 5 megahertz (MHz) to 100 MHz, or higher. In one embodiment, the RF frequency of the RF power signal provided by the RF power source 195 ranges between 1 to 30 megahertz (MHz). Further, the RF frequency may be a baseline frequency of 10 MHz or 13.56 MHz or 27 MHz or 40MHz or 60 MHz or 100 MHz. In one implementation, the frequency of operation of the RF power source 195 is 10 MHz.

[0056] In one embodiment, the at least one TCP coil 310 is placed at the outer edge of the top electrode 324. In particular, the at least one TCP coil 310 is located near (e.g., disposed over) the dielectric 125 that surrounds the top electrode 324. The dielectric may be configured as a ceramic type material, or any other material that is capable of allowing energy (e.g., toroidal power) to pass from the at least one TCP coil 310 to the plasma processing chamber 102. In one embodiment, the at least one TCP coil 310 and/or the dielectric 125 overlaps at least a portion of the edge ring 126, such as in a vertical direction. In another embodiment, the at least one TCP coil 310 and/or the dielectric 125 is disposed beyond an outer edge of the edge ring 126, such as in the vertical direction, as shown in FIG. 3. More specifically, RF power that is applied to the at least one TCP coil 310 is configured to provide inductively coupled power into the plasma processing chamber 102 for the formation of plasma, which can further enhance etching of the surface of the substrate. For example, the RF power provided by the at least one TCP coil 310 is used to mitigate edge heavy non-uniformity in the plasma (e.g., plasma generated through capacitive coupling). In particular, the TCP coil provides an tuning parameter to affect plasma generation across the substrate, and more particularly at the edge of the substrate. That is, one or more characteristics of the RF power signal to the TCP coil may be selectable to help achieve uniform plasma generation globally across the substrate, and especially at the edge of the substrate, by providing for uniform ion density and/or flux globally across the substrate, which in turn provides for selective control of angular ion tilt globally across the substrate. In that manner, at least one TCP coil 310 beneficially influences the uniformity of plasma, such that ion tilt may be more vertical (i.e., perpendicular to the surface of the substrate) when striking the substrate, especially at the edge of the substrate.

[0057] FIG. 4A illustrates plasma density and sheath across the wafer contributing to tilting of ions striking a substrate undergoing processing within a plasma processing system that does not include the improvements described herein, such as the split top electrode, etc. In particular, FIG. 4A focuses on a substrate 120’ that is supported by an electrostatic chuck (ESC) 118’ during processing. Edge ring 126’ may surround the ESC 118’, and is configured to perform many functions including, but not limited to, positioning the substrate 120’ on the ESC 118’, confining plasma to an area above the substrate 120’, protecting the ESC 118’ from erosion by ions of the plasma, and shielding underlying components of the plasma chamber from being damaged by ions of the plasma, improve performance at the edge of the substrate, etc.

[0058] In general, a plasma processing system generates a plasma. A plasma density profile 420A of the plasma is generated in part responsive to a bias RF power signal placed on the ESC 118’. As shown, in plasma processing systems that do not include the improvements described herein (e.g., split top electrode, etc.), the plasma density profile may have a center heavy profile towards and/or across a center (not shown) or interior of the substrate 120’. For example, these systems that do not include the improvements described herein (e.g., split top electrode, etc.) may include a top electrode (not shown) applying a high frequency RF signal (e.g., 60 MHz) for increased plasma density, and a bias signal of low frequency (e.g., 400 kHz) applied to the ESC 118’ (e.g., lower electrode in the ESC) to increase ion energy for faster etching and/or a mixed bias signal including low and high frequencies in the bias signal. For illustration, because high frequencies (i.e., to the top electrode) are used to generate high density plasma in systems that do not include the improvements described herein (e.g., split top electrode, etc.), the center heavy profile may be caused by non-uniform plasma generation and loss to the chamber wall. In addition, the center heavy plasma non-uniformity may be a result of slowing of the electromagnetic wave termed as standing wave formation at higher frequencies. Further, the plasma density profile 420 is horizontal across the interior of the substrate 120’ beyond the center illustrating uniformity of the plasma, but rolls off downwards along the remaining substrate radial length, i.e., radially towards the edge of the substrate. As such, additional nonuniformity of the plasma density profile may show up mid-wafer (i.e., approximately half way from the center to the edge), and sometimes even earlier (i.e., more towards the center).

[0059] Also, a sheath thickness 410A is generally inversely proportional to the square root of plasma density profile 420A. The sheath defines an area where there is a depletion of electrons, and is located on or near the surface of the substrate. As shown, the sheath thickness is also non-uniform initially near the center of the substrate 120’ (i.e., becoming thinner or falling downwards) in plasma processing systems that do not include the improvements described herein (e.g., split top electrode, etc.), and is further deformed as the substrate radial length progresses, such that the sheath thickness rises upwards at the edge of the substrate. As shown, the sheath may include a bend beginning at mid-wafer (i.e., approximately half way from the center to the edge), and sometimes even earlier (i.e., towards the center).

[0060] Ions escaping the plasma and pulled towards the substrate 120’, by electric field of the sheath originated from the RF power signal, travel perpendicular to the sheath thickness 410A. As shown, ions 415C near the center of the wafer, where the plasma is non-uniform, escape the plasma at an angle that is perpendicular to the surface of the sheath, as defined by the sheath thickness 410A. This contributes to ion tilt (i.e., offset from vertical), and tilt of the etched features near the center of the wafer. On the other hand, in the interior of the substrate 120’, between the center and the edge, plasma is uniform and ions 415A escape the plasma and travel in a vertical direction (i.e., perpendicular to the surface of the sheath) towards the substrate 120’, which is desirable. Furthermore, ions 415B located where plasma non-uniformity appears towards the edge of the substrate 120’, again exit the plasma at an angle due to the rising or increasing sheath thickness 410A. As such, towards the edge of the substrate 120’, ions 415B also have a tilt that is offset from vertical (i.e., the angle from vertical that the ions are traveling). The ion tilt introduced on the substrate due to plasma non-uniformity contributes to unexpected etch features (e.g., near the center and towards the edge of the substrate) resulting from this ion tilt. For example, when etching the substrate, the etching features of the substrate where nonuniformity or this sheath bending takes place will be angled (i.e., etched at an angle) and not vertical (i.e., etched vertically), whereas in uniform plasma, the etching features will be vertically oriented.

[0061] FIG. 4B illustrates plasma density and sheath on a substrate undergoing processing within the plasma processing systems and hybrid plasma processing systems of FIGS. 1A, 2, and 3, in accordance with embodiments of the present disclosure. Uniformity of the plasma density on the substrate 120 is achieved, as previously described in embodiments of the present disclosure, by splitting a top electrode of a CCP or hybrid CCP/TCP chamber into two or more sections, and/or by stepping a thickness of one of the sections in the split top electrode, wherein each section delivers separate high frequency power to generate plasma that can be adjusted to produce plasma uniformity globally across the substrate; and/or by positioning a TCP source above a gap of the split top electrode of the hybrid CCP/TCP chamber or at the edge of a long top electrode used for generating capacitively coupled plasma, wherein TCP power can be produced to generate inductively coupled plasma in order to mitigate edge or center heavy plasma non-uniformity.

[0062] In general, the plasma processing system and hybrid plasma processing systems of FIGS. 1 A, 2, and 3 each generates a plasma. The plasma density profile 420B of the generated plasma is generated in part responsive to the bias RF power signal placed on the ESC 118. As shown, the plasma density profile is horizontal initially across the interior of the substrate 120 (i.e., towards the center of the substrate), and remains uniformly horizontal across the rest of the substrate 120. As such, the plasma density profile 420B is uniform globally across the entirety of the surface of the substrate 420, and in particular at the center of the substrate, and further at the edge of the substrate shown partly in the highlighted area 450.

[0063] Also, a sheath thickness 410B is generally inversely proportional to the square root of plasma density profile 420B. The sheath defines an area with an electric field where there is a depletion of electrons, and is located on the substrate or wafer. As shown, the sheath thickness is also horizontal initially on the substrate 120 (i.e., towards the center of the substrate), and remains uniformly horizontal across the rest of the substrate. As such, the sheath thickness is also uniform across the entirety of the surface of the substrate, and in particular at the center of the substrate, and further at the edge of the as is shown partly in the highlighted area 450.

[0064] Ions escaping the plasma and pulled towards the substrate 120 in part by the bias RF power signal travel perpendicular to the sheath thickness 410B. That is, ions 415D within the interior of the substrate 105 (i.e., towards the center) escape the plasma and travel in a vertical direction towards the substrate 105. Because the sheath thickness 41 OB is uniform across the surface of the substrate, to include the edge of the substrate, ions 415E at the edge of the substrate also exit the plasma in the vertical direction (i.e., perpendicularly from the horizontal sheath thickness 410B. That is, ions 415D and 415E do not have a tilt, or the ion tilt from vertical is significantly reduced. In that manner, features across the entirety of the substrate (e.g., globally) are uniform, such that features formed at the edge of the substrate are substantially similar to features formed in the interior of the substrate (i.e., towards the center). For example, when etching the substrate, the etching features throughout the interior and at the edge of a substrate will be vertically oriented (i.e., etched vertically).

[0065] In embodiments, a substrate positioning program may include program code for controlling chamber components that are used to load the substrate onto a pedestal or chuck and to control the spacing between the substrate and other parts of the chamber such as a gas inlet and/or target, which may be implemented by control system or controller 150 of FIG. 1. In some implementations, a controller is part of a system, which may be part of the abovedescribed examples. Such systems can comprise semiconductor processing equipment, including a processing tool or tools, chamber or chambers, a platform or platforms for processing, and/or specific processing components (a substrate pedestal, a gas flow system, etc.). These systems may be integrated with electronics for controlling their operation before, during, and after processing of a semiconductor wafer or substrate. The controller, depending on the processing requirements and/or the type of system, may be programmed to control any of the processes disclosed herein, and process implemented for operating a plasma chamber. Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files), defining operational parameters for carrying out a particular process on or for a semiconductor substrate or to a system. The operational parameters may, in some embodiments, be part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and/or dies of a wafer.

[0066] The controller, in some implementations, may be a part of or coupled to a computer that is integrated with, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the “cloud” of all or a part of a fab host computer system, which can allow for remote access of the substrate processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process. In some examples, a remote computer (e.g., a server) can provide process recipes to a system over a network, which may include a local network or the Internet.

[0067] Without limitation, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, a plasma enhanced chemical vapor deposition (PECVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing systems that may be associated or used in the fabrication and/or manufacturing of semiconductor wafers.

[0068] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

[0069] Although the foregoing embodiments have been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications can be practiced within the scope of the appended claims. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the embodiments are not to be limited to the details given herein, but may be modified within their scope and equivalents of the claims.

Claims

1. A system, comprising: a plasma chamber configured for generating plasma, wherein the plasma chamber includes a lower electrode located within an electrostatic chuck (ESC) having a central axis in a vertical direction; a split top electrode disposed above the lower electrode, wherein the split top electrode includes a main electrode and an outer electrode surrounding the main electrode in a horizontal direction referenced to the central axis; a dielectric separating the main electrode and the outer electrode; at least one transformer coupled plasma (TCP) coil vertically disposed over the split top electrode; and an edge ring surrounding the lower electrode and ESC in the horizontal direction.

2. The system of claim 1, wherein the dielectric overlaps at least a portion of the edge ring in a vertical direction, wherein the at least one transformer coil is disposed over the dielectric.

3. The system of claim 1, wherein the dielectric separating the main electrode and the outer electrode ranges between 2 to 55 millimeters (mm) in a horizontal direction.

4. The system of claim 1, further comprising: a vertical height difference between a bottom surface of the main electrode above a top surface of the ESC and a bottom surface of the outer electrode above the top surface of the ESC.

5. The system of claim 4, wherein the bottom surface of the outer electrode is closer to the top surface of the ESC than the bottom surface of the main electrode.

6. The system of claim 4, wherein the bottom surface of the outer electrode is further away from the top surface of the ESC than the bottom surface of the main electrode.

7. The system of claim 1, further comprising: a C-shroud surrounding the split top electrode and the edge ring in the horizontal direction.

8. The system of claim 1, further comprising: wherein the dielectric includes an interlocking step configured to interface with the main electrode, wherein the main electrode includes an opposing interlocking step configured to mate with the interlocking step of the dielectric.

9. The system of claim 1, wherein the at least one TCP coil includes: a plurality of coils oriented vertically over the split top electrode.

10. The system of claim 1, wherein the at least one TCP coil includes: a plurality of coils oriented horizontally over the split top electrode.

11. The system of claim 1, further comprising: a first radio frequency (RF) power generator electrically coupled to the main electrode and configured to supply a high frequency RF power signal to the main electrode; a second RF power generator electrically coupled to the outer electrode and configured to supply a low frequency RF power signal to the outer electrode; and a power generator electrically coupled to the lower electrode and configured to supply a bias signal to the lower electrode.

12. The system of claim 11, wherein the bias signal is a direct current bias signal.

13. The system of claim 11, wherein the bias signal is a RF bias signal including at least one of a low frequency signal and a high frequency signal.

14. The system of claim 11, further comprising: a third RF power generator electrically coupled to the at least one TCP coil, and configured to supply an RF power signal to the at least one TCP coil.

15. A system, comprising: a plasma chamber configured for generating plasma, wherein the plasma chamber includes a lower electrode located within an electrostatic chuck (ESC) having a central axis in a vertical direction; an edge ring surrounding the lower electrode and ESC in a horizontal direction referenced to the central axis; a top electrode disposed above the lower electrode, wherein the top electrode extends radially beyond the edge ring in the horizontal direction; and at least one transformer coupled plasma (TCP) coil vertically disposed over the long electrode.

16. The system of claim 15, wherein the at least one TCP coil is disposed over the dielectric radially beyond the edge ring in the horizontal direction.

17. The system of claim 15, wherein the at least one TCP coil that is disposed over the dielectric overlaps the edge ring in the vertical direction.

18. The system of claim 15, further comprising: a C-shroud surrounding the top electrode and the edge ring in the horizontal direction.

19. The system of claim 15, wherein the at least one TCP coil includes: a plurality of coils oriented vertically over the top electrode.

20. The system of claim 15, wherein the at least one TCP coil includes: a plurality of coils oriented horizontally over the top electrode.

21. The system of claim 15, further comprising: a first radio frequency (RF) power generator electrically coupled to the top electrode, and configured to supply a first RF power signal to the top electrode, wherein the first RF power signal is operating at a first frequency; a second RF power generator electrically coupled to the at least one TCP coil, and configured to supply a second RF power signal to the at least one TCP coil, wherein the second RF power signal is operating at a second frequency; and a power generator electrically coupled to the lower electrode and configured to supply a bias signal to the lower electrode.

22. The system of claim 21, wherein the bias signal is a direct current bias signal.

23. The system of claim 21, wherein the bias signal is a RF bias signal including at least one of a low frequency signal and a high frequency signal.

24. A system, comprising: a plasma chamber configured for generating plasma, wherein the plasma chamber includes a lower electrode located within an electrostatic chuck (ESC) having a central axis in a vertical direction; a split top electrode disposed above the lower electrode, wherein the split top electrode includes a main electrode and an outer electrode surrounding the main electrode in a horizontal direction referenced to the central axis; a dielectric separating the main electrode and the outer electrode; an edge ring surrounding the lower electrode and ESC in the horizontal direction; and a vertical height difference between a bottom surface of the main electrode above a top surface of the ESC and a bottom surface of the outer electrode above the top surface of the ESC.

25. The system of claim 24, wherein the dielectric overlaps at least a portion of the edge ring in a vertical direction.

26. The system of claim 24, wherein the dielectric separating the main electrode and the outer electrode ranges between 2 to 55 millimeters (mm) in a horizontal direction.

27. The system of claim 24, wherein the bottom surface of the outer electrode is closer to the top surface of the ESC than the bottom surface of the main electrode.

28. The system of claim 24, wherein the bottom surface of the outer electrode is further away from the top surface of the ESC than the bottom surface of the main electrode.

29. The system of claim 24, further comprising: a C-shroud surrounding the split electrode and the edge ring in the horizontal direction.

30. The system of claim 24, further comprising: wherein the dielectric includes an interlocking step configured to interface with the main electrode, wherein the main electrode includes an opposing interlocking step configured to mate with the interlocking step of the dielectric.

31. The system of claim 24, further comprising: a first radio frequency (RF) power generator electrically coupled to the main electrode and configured to supply a high frequency RF power signal to the main electrode; a second RF power generator electrically coupled to the outer electrode and configured to supply a low frequency RF power signal to the outer electrode; and a power generator electrically coupled to the lower electrode and configured to supply a bias signal to the lower electrode.

32. The system of claim 31, wherein the bias signal is a direct current bias signal.

33. The system of claim 31, wherein the bias signal is a RF bias signal including at least one of a low frequency signal and a high frequency signal.

34. The system of claim 31, further comprising: a third RF power generator electrically coupled to the at least one TCP coil, and configured to supply an RF power signal to the at least one TCP coil.